Dural sinus thrombosis

Dural sinus thrombosis (DST) is a condition where a blood clot forms in one of the dural sinuses. The dural sinuses are located in your head. They drain deoxygenated blood as well as cerebrospinal fluid (CSF) that surrounds your brain, and empties them into the internal jugular vein that takes it back to your heart and lungs to be re-oxygenated. They are called venous sinuses instead of regular veins because they are larger in size and have a more hollowed out cavity to hold the blood and CSF.

Cause

Just as blood clots can form elsewhere in the body, such as in the arteries of the brain (which is called a stroke), or in the deep veins of the legs (which is called a deep venous thrombosis or DVT), blood clots can also form in the dural sinuses of the head. The conditions that predispose a person to stroke and DVTs can also lead to DST. These conditions can include: infection, pregnancy (postpartum), oral contraceptives, dehydration and extreme malnourishment, cardiac disease, ulcerative colitis, sickle cell trait, trauma, postoperatively, malignant tumors, hypercoagulable blood disorder (e.g. lupus), and diabetes mellitus.

When there is slow blood flow in the veins the blood tends to clot just as it would when you cut yourself. But instead this is within the blood vessel. When a blood clot forms it can block the blood flow. If the outflow is blocked then the blood backs up and slows down the blood coming in. This creates an enlargement of the dural sinus. It can result in a stroke, brain swelling, and brain hemorrhage.

Symptoms and diagnosis

Symptoms can include headache, nausea, vomiting, seizures, numbness/weakness, blurred vision, confusion. If severe, it may cause coma and death. It may often be diagnosed through special types of CT scans or MRI. Angiography is occasionally indicated for evaluation. Laboratory tests may be necessary to determine the cause of the thrombosis.

Treatment

Treatment needs to be started quickly to prevent damage to the brain. The underlying cause is treated if known. Treatment of the thrombosis most often requires a blood thinner, such as heparin or Coumadin. In extremely rare and severe cases, a 'clot buster', such as tPA, can be used to dissolve the clot by directly administering it to the clot through a catheter guided into the veins of the brain.

Hypertension and any seizures are closely controlled with medication. Brain swelling, if severe, may require a procedure such as ventriculostomy or craniotomy to relieve the pressure.